1. Field of the Invention
The present invention relates to a tool life management system for managing the lives of tools, and more particularly, to a tool life management system for an NC machine tool.
2. Description of the Related Art
It is widely known to manage the lives of tools used in NC machine tools. In one of such tool life managing methods, tool life is managed on the basis of the time periods for which the tools are used or the number of times the tools are used. This method, however, takes no account of differences in machining load and thus cannot manage the lives of tools with accuracy.
In view of this, there has been proposed a method of monitoring wear of tools based on change in load torque of the spindle, etc.
This conventional method, however, requires that the degree of change in load torque of the spindle be obtained empirically or statistically, making it necessary to carry out machining experiment or statistical process a considerable number of times. This method, therefore, requires a great deal of labor and skill.